Technical Abstract:
Inscent, Inc. has developed methodologies for rapidly screening potential ligands of chemosensory proteins (CSPs) isolated from the antennae of target insects. These novel ligands, referred to as Arometics, mimic naturally-occurring odorants and may function as super-stimuli because of their strong affinity to chemosensory proteins. CSPs from the Asian citrus psyllid (ACP) antennae were identified based on their reactivity to Petitgrain oil. Several ligands were identified that bound these CSPs; they were then subjected to two behavioral assays to measure their biological activity. One assay measured probing frequency into a line of emulsified wax (SPLAT®, ISCA Technologies) containing the ligand. The second measured the retention time of ACP in a perforated foil cup that emitted an airstream carrying the ligand. One ligand, nicknamed ‘Titan’, induced significantly more probing than did limonene, a common citrus volatile and known ACP attractant. A mixture of Titan and limonene induced a probing level that was twice as high as limonene alone and significantly higher than Titan alone. This result showed that, when mixed with certain terpenes, Titan had a synergistic effect on psyllid response. In the olfactometer, there was no difference between ACP response to Titan and to the odor of orange jasmine flush, demonstrating that ACP could detect Titan via olfaction alone. As in the probing test, a mixture of limonene and Titan was also significantly more stimulatory than limonene alone. These results indicate that Titan is highly biological active, and that it could potentially be used to enhance the attractiveness of citrus volatiles.